DESCRIPTION: (Applicant?s Abstract) The overall goal of the proposed research study is to improve treatment outcomes for drug use and medical care among human immunodeficiency virus (HIV) infected injection drug users (IDUs) undergoing methadone treatment. Methadone maintenance treatment (MMT) is a widely applied and highly effective treatment available for IDUs who are opioid dependent, yet it has limitations. For example, while methadone treatment significantly reduces the use of heroin, it does not completely eliminate opiate use in all patients. Furthermore, the use of non-opiates such as stimulants, alcohol, and other drugs is not as robustly reduced in MMT patients as is the use of opiates. Continued drug use by HIV-infected IDUs increase the risk for other infectious diseases. Drug use may also cause problems with HIV health care by interfering with appointment keeping and adherence to medical regimens. It is therefore essential to find ways to improve the effectiveness of MMT with respect to both drug use and medical care in HIV-infected persons. The proposed study will consist of a six month randomized trial to test the efficacy of incentives in the form of contingent vouchers designed to improve the treatment outcome of HIV-infected MMT patients in the domains of drug use and HIV medical care. 150 HIV-infected MMT patients will be randomized to one of three treatment conditions: 1) a Drug Voucher group that will be given incentives to reinforce drug-free urine tests, 2) a Drug plus Medical Voucher group that will be given incentives to reinforce both drug-free urines and HIV "Medical Care Management" appointment keeping, and 3) a No Voucher control group that will receive no incentives. Participants in the study will be able to exchange vouchers for goods and services of their choice. The main outcomes will consist of drug use, medical appointment keeping, HIV and drug-related medical morbidity, and HIV and drug-related health care costs.